Got a slow computer? Before you assume it’s time for a new one, it’s worth asking a simple question: could something you’re doing every day be causing the problem?
The truth is, many of the most common reasons for a slow computer have nothing to do with age or hardware. They’re everyday habits — often completely innocent ones — that quietly add up over time and leave your computer struggling to keep up.
Here at OJ Computers, we see this all the time. People bring in computers they think are worn out, and a bit of cleaning up and a few tweaks have them running like new again. So we’ve put together this basic guide to help you understand what might be slowing your PC down — and what you can do about it.
1. Never Restarting Your Computer
If your computer runs for days or even weeks without a restart, it accumulates a lot of temporary data in its memory (RAM). Over time, this builds up and your PC has to work harder and harder to manage it all. Programs start to lag, and simple tasks take longer than they should. A restart clears all of this out and gives your system a fresh start.
✅ Quick fix: Restart your computer at least once every couple of days — or every day if you use it heavily. It only takes a minute and makes a real difference. If this doesn’t improve your slow computer, it’s probably time to chat to us about a service.
2. Keeping Too Many Browser Tabs Open
We’ve all been there — ten, twenty, thirty browser tabs open “just in case”. Each open tab is actively using your computer’s memory and processing power, even if you’re not looking at it. The more tabs you have, the more your system is juggling behind the scenes, and the slower everything feels.
✅ Quick fix: Try to close tabs you’re not actively using. If you want to save something for later, bookmark it. Your computer (and your sanity) will thank you.
3. Letting Programs Start Automatically When You Turn On Your PC
Every time you install a new program, it often quietly adds itself to the list of things that start up automatically when your computer turns on. Over time, you can end up with dozens of programs all trying to load at once. This is one of the most common reasons people find their PC takes ages to be ready to use after switching it on.
✅ Quick fix: On Windows 11, press Ctrl + Shift + Esc to open Task Manager, then click the Startup tab to see what’s loading automatically. You can disable anything you don’t need starting immediately. If you’re not sure what’s safe to turn off, give us a call on 8552 4442.
4. Never Clearing Out Old Files and Downloads
That Downloads folder can quietly grow to gigabytes over the years — installers, old photos, documents you’ve long since forgotten about. A full hard drive, or one that’s nearly full, forces your computer to work much harder to find and store information. Windows also needs a certain amount of free space to run properly.
✅ Quick fix: Set aside 15 minutes to go through your Downloads folder and delete anything you no longer need. Empty your Recycle Bin too — files in the bin still take up space until you do.
5. Skipping Windows Updates
We know — those “Windows needs to update” notifications can feel like they always appear at the worst possible time. But skipping updates for weeks or months means your system is running older, less efficient code. Updates don’t just fix security vulnerabilities; they often include performance improvements and bug fixes that help your slow computer run more smoothly.
✅ Quick fix: Let Windows update regularly, ideally overnight or when you’re not using the computer. Go to Settings > Windows Update to check what’s waiting. Not sure how to do this? Get in touch with us. We include actioning all the outstanding updates when we service your computer.
6. Running Without Proper Antivirus Protection
Malware and viruses don’t just put your personal information at risk — they can seriously slow your computer down. Some malicious programs run constantly in the background, using up your processing power and internet connection without you knowing. If your computer has suddenly become much slower for no obvious reason, a virus or malware infection is worth considering.
✅ Quick fix: Make sure you have active, up-to-date security software running on your PC. We recommend ESET Security — it’s effective, lightweight, and won’t slow your system down the way some other security tools can. OJ Computers can help you get it set up.
7. Ignoring Low Storage Warnings
When your hard drive or SSD gets too full — generally below about 10-15% free space — your computer starts to struggle. Windows needs free space to create temporary files, run system processes, and even install updates. A nearly-full drive can make even simple tasks feel sluggish.
✅ Quick fix: Check your storage by opening File Explorer and looking at your C: drive. If it’s more than about 85% full, it’s time to delete files, move things to an external drive, or consider an upgrade. OJ Computers can help if you’re not sure where to start.
8. Not Cleaning the Physical Computer
This one surprises a lot of people. Dust builds up inside desktop computers and laptops over time, clogging the vents and fans that keep the system cool. When a computer can’t cool itself properly, it slows down automatically to protect itself from overheating — a process called thermal throttling. Your computer might be running slow simply because it’s too hot.
✅ Quick fix: For laptops, make sure the vents underneath and on the sides are not blocked (avoid using them on soft surfaces like beds or couches). For desktops, an annual clean-out of dust can make a noticeable difference. We can do this for you if you’d prefer to leave it to the professionals.
9. Installing Lots of Programs You Rarely Use
Each program you install doesn’t just sit quietly on your hard drive. Many run background processes, schedule updates, and use system resources even when you’re not actively using them. A computer with 50 programs installed and rarely used is carrying a lot of unnecessary weight.
✅ Quick fix: Go through your installed programs list (Settings > Apps) and uninstall anything you haven’t used in the last few months. If you’re not sure whether something is safe to remove, bring your slow computer in and we can take a look.
10. Using an Old, Unsupported Operating System
If you’re still running Windows 10, it’s worth knowing that Microsoft ended support for it in October 2025. Your device is no longer receiving security updates — making it increasingly vulnerable and, over time, less compatible with new software. An unsupported operating system can gradually become slower and more problematic as software developers stop optimising for it.
✅ Quick fix: Upgrading to Windows 11 is often straightforward on modern hardware. If your current PC can’t run Windows 11, it might be time to consider an upgrade. Talk to us and we can let you know your options.
Still Struggling With A Slow Computer?
Sometimes a slow computer does need a professional eye. Whether it’s a hardware issue, a virus, a failing hard drive, or just years of clutter that needs clearing out — the team at OJ Computers is here to help.
We’ve been helping people across Victor Harbor, Goolwa, Port Elliot, Strathalbyn, the Adelaide Hills and surrounding areas for nearly 30 years to overcome the problem of a slow computer. We offer honest, friendly advice and won’t suggest an expensive fix when a simple one will do.
We can look at your computer in-store, or in many cases help you remotely without you even needing to leave home.
Phone us: 08 8552 4442
Visit us: 268 Port Elliot Road, Victor Harbor
Office Hours: Monday–Friday, 9am–12noon (mobile and remote services available afternoons)